Fish tail bit



Feb. 16, 1932. H. Mc 1,845,168

FISH TAIL BIT Filed Aug. 31. 192" 20 d g 43 5M firroelvey Patented Feb. 16, 1932 UNITED STATES PATENT OFFICE HENRY MCHALEY, F LONG BEACH, CALIFORNIA, ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, 0F ONE-HALF TO GEORGE G. CUNNINGHAM AND ONE-HALF TO VINCENT R. CUNNINGHAM, BOTH 01 LOS ANGELES, CALIFORNIA FISH TAIL B11 4 Application filed August 31, 1927. Serial No. 216,582.

My invention relates to the art of deep well ed pin 11 thereon for attachment to the drilldrilling being more particularly a form of ing string in the usual manner. bit for use in drilling wells by the rotary 12 designates the bit body which extends method of drilling. Bits of the character downwardly from the head in the form of a referred to usually weigh from three hundred flat member, consisting of two legs 13, joined in to fivehundred pounds, are costly, and require centrally by a web 14. These legs 13 are frequent sharpening to keep' the same in slightly offset with relation to each other, as proper condition for performing their funcshown in Figs. 2 and 4, diverging downward tion in advancing the hole. It follows that and outwardly from a common plane directly when the sharpening operation is necessary, under the head 10. G0 the entire bit must be removed from the The legs 13 are recessed at their lower pordrilling string by breaking the joint at the tion on opposite faces as indicated at 16, the head of the bit, which j oint-is ordinarily the upper end of such recesses forming shoulders hardest joint in the string to break. 17 undercut to engage a correspondingly 15 The principal object of my invention is to shaped rib 18, formed on the upper end of 85 provide a removable blade for bits of the a blade which, in general may be of any fish-tail type, of simple form and construcsuitable form. These shoulders take the uption, which may be readily removed from the thrust on the blade and being undercut firm- -bit proper. ly, hold the blade against outward twist at 20 By providing such a removable blade, of a its upper. end.

weight of fifteen or twenty pounds, it 1s m- The blade 20 extends transversely of the mediately apparent that by having on hand bit and between the legs 13, fitting in the rea number of such blades that the change from cesses 16 formed in the legs, the lower end a dull bit to a sharp one may be quickly made f th l 13 b i b hi d th ti f 2 with considera ly l f r h n n cases the blade engaged thereby when rotated as where the whole bit must be removed- I IS in the direction of the arrow in Fig. 4. to be noted also, that the blades may be made The blade 20 is ecured to the legs 13 by of material considerably harder than the body m a f h d d b lt 22 h ld in la by of the bit, at less expense than where the ena tt i 22, It i t b t d th t a 1 30 tire bit is hardened or consists of consequentitudi l h l 23 i f d o h id 1y more e pensive meterlalof the bit body which receives astream of 0ther bjects n dv g 1 a Pe flush water from ducts 24, indicated in dotted hereinafter, from the following description lines in Figs. 1 and 2, and that the blade 20 is and drawings. 0 provided on opposite sides with a In or pro- 35 Referring to the drawings wh1ch are for j ti 25, engaged b th inne e ge of a illustrative purposes only, cooperating leg 13 whichtakes the side thrust F i a face v1ew, 1n elevat;10n, of a blt, of the blade. The lugs 25 are tapered on one embodying a form of my 1I1Ve11t10I1- face as indicated at 26, for directing wash Flg. 2 1s a slde eleva l n the blt ShOWIl fluid from the corresponding channel 23 to- 40 1n Flg. 1. ward the exposed face of the blade.

3 is a perspective VleYV Of the blade For the purpose of more shown on the bit in the pr mg g the blade in fixed relation to the legs 13, I Fig. 4 is a sectional plan view on line 4.-4 may provide the blade with ribs 18, the upof Fig. 1, and per face of which is angularly disposed to 45 Fig. 5 is a modified form of construction, engage the angular lower face 13 of the illustrating a simplified form of my invenle s 13. tion. or the purpose of mixing the mud formed More particularly describing the embo'diby the cuttings from the bit mixed with the ment of my invention shown in the drawings, fluid heretofore referred to, I may provide 10 designates a head havingatapered threadholes 27 formed in the body and notches in the edges or sides of the body In the form shown in Fig. 5,

as shown at 28. the legs 13 are of the same construction as shown in the preceding figures, except not Jmdercut.

What I claim is:

A fish tail bit comprising: on said body having 1 throu h, legs on said ofiset parallel relation, a web interspace osed between and connecting disposed channels commuorm oppositely the shoulder 17 is a body, a head flu' passages therebody terminating in said legs to nicating with said fluid passages in the head,

a blade secured to said legs,

blade for directing fiuidfrom said and lugs on said channels to the opposite faces of said blade.

In testimony my hand at Los day of August, 1927.

whereof, I have hereunto set Angeles, California, this 6th HENRY MOHALEY; 

